Iterating with foreach
foreach element in array do statement
foreach element in array collect statement
for
loops to iterate over an array, it is easy to get the beginning or ending index wrong. Consider the irksome fact that only two of the following for
loops correctly indexes through array
elements:
for i := 1 to Length(array) do Print(array[i]); for i := 1 to Length(array) - 1 do Print(array[i]);
for i := 0 to Length(array) - 1 do Print(array[i]); for i := 0 to Length(array) do Print(array[i]); for i := 1 to Length(array) do Print(array[i - 1]);To avoid this morass, NewtonScript provides you with a bulletproof
for
loop--foreach
.
A foreach
loop iterates over each element in an array automatically. Here is the same example using the much simpler syntax of foreach
:
foreach element in array do Print(element);The
element
variable is a loop variable similar to the i
loop variable found in the previous examples. There is a crucial difference between the two, however. The element
loop variable does not take on successive index values (0
, 1
, etc.), but rather takes on successive element values (array[0]
, array[1]
, etc.).
As is the case with a standard for
loop, the loop variable in foreach
can be named anything--be it a single letter or a song:
foreach yellowSubmarine in array do Print(yellowSubmarine);
An online version of Programming for the Newton using Macintosh, 2nd ed. ©1996, 1994, Julie McKeehan and Neil Rhodes.
Last modified: 1 DEC 1996